scholarly journals Electrophysiological investigation of intact retina with soft printed organic neural interface

2021 ◽  
Author(s):  
Ieva Vebraite-Adereth ◽  
Moshe David-Pur ◽  
David Rand ◽  
Eric Glowacki ◽  
Yael Hanein
Keyword(s):  
Electrical Stimulation ◽  
Ex Vivo ◽  
Electrode Array ◽  
Carbon Electrodes ◽  
Natural Image ◽  
Neural Firing ◽  
Electrode Arrays ◽  
Electrical Recording ◽  
Research Activities

Abstract Objective. Understanding how the retina converts a natural image or an electrically stimulated one into neural firing patterns is the focus of on-going research activities. Ex vivo, the retina can be readily investigated using multi electrode arrays. However, multi electrode array recording and stimulation from an intact retina (in the eye) has been so far insufficient. Approach. In the present study, we report new soft carbon electrode arrays suitable for recording and stimulating neural activity in an intact retina. Screen-printing of carbon ink on 20 µm polyurethane (PU) film was used to realize electrode arrays with electrodes as small as 40 µm in diameter. Passivation was achieved with a holey membrane, realized using laser drilling in a thin (50 µm) PU film. Plasma polymerized EDOT was used to coat the electrode array to improve the electrode specific capacitance. Chick retinas, embryonic stage day 13, both ex-planted and intact inside an enucleated eye, were used. Main results. A novel fabrication process based on printed carbon electrodes was developed and yielded high capacitance electrodes on a soft substrate. Ex vivo electrical recording of retina activity with carbon electrodes is demonstrated. With the addition of organic photo-capacitors, simultaneous photo-electrical stimulation and electrical recording was achieved. Finally, electrical activity recordings from an intact chick retina (inside enucleated eyes) were demonstrated. Both photosensitive retinal ganglion cell responses and spontaneous retina waves were recorded and their features analyzed. Significance. Results of this study demonstrated soft electrode arrays with unique properties, suitable for simultaneous recording and photo-electrical stimulation of the retina at high fidelity. This novel electrode technology opens up new frontiers in the study of neural tissue in vivo.

scholarly journals A mm-Sized Free-Floating Wireless Implantable Opto-Electro Stimulation Device

Micromachines ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 621
Author(s):  
Yaoyao Jia ◽  
Yan Gong ◽  
Arthur Weber ◽  
Wen Li ◽  
Maysam Ghovanloo
Keyword(s):  
Electrical Stimulation ◽  
Large Scale ◽  
Electrode Array ◽  
Cmos Process ◽  
Optical Stimulation ◽  
In Vivo Experiments ◽  
Stimulation Mode ◽  
Shift Keying ◽  
On Chip

Towards a distributed neural interface, consisting of multiple miniaturized implants, for interfacing with large-scale neuronal ensembles over large brain areas, this paper presents a mm-sized free-floating wirelessly-powered implantable opto-electro stimulation (FF-WIOS2) device equipped with 16-ch optical and 4-ch electrical stimulation for reconfigurable neuromodulation. The FF-WIOS2 is wirelessly powered and controlled through a 3-coil inductive link at 60 MHz. The FF-WIOS2 receives stimulation parameters via on-off keying (OOK) while sending its rectified voltage information to an external headstage for closed-loop power control (CLPC) via load-shift-keying (LSK). The FF-WIOS2 system-on-chip (SoC), fabricated in a 0.35-µm standard CMOS process, employs switched-capacitor-based stimulation (SCS) architecture to provide large instantaneous current needed for surpassing the optical stimulation threshold. The SCS charger charges an off-chip capacitor up to 5 V at 37% efficiency. At the onset of stimulation, the capacitor delivers charge with peak current in 1.7–12 mA range to a micro-LED (µLED) array for optical stimulation or 100–700 μA range to a micro-electrode array (MEA) for biphasic electrical stimulation. Active and passive charge balancing circuits are activated in electrical stimulation mode to ensure stimulation safety. In vivo experiments conducted on three anesthetized rats verified the efficacy of the two stimulation mechanisms. The proposed FF-WIOS2 is potentially a reconfigurable tool for performing untethered neuromodulation.

scholarly journals Graphene-based carbon-layered electrode array technology for neural imaging and optogenetic applications

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Dong-Wook Park ◽  
Amelia A. Schendel ◽  
Solomon Mikael ◽  
Sarah K. Brodnick ◽  
Thomas J. Richner ◽  
...  
Keyword(s):  
Soft Tissues ◽  
Electrode Array ◽  
Electrode Arrays ◽  
Neural Imaging ◽  
Brain Surface ◽  
Array Technology ◽  
Micro Electrode Arrays ◽  
The Brain

Abstract Neural micro-electrode arrays that are transparent over a broad wavelength spectrum from ultraviolet to infrared could allow for simultaneous electrophysiology and optical imaging, as well as optogenetic modulation of the underlying brain tissue. The long-term biocompatibility and reliability of neural micro-electrodes also require their mechanical flexibility and compliance with soft tissues. Here we present a graphene-based, carbon-layered electrode array (CLEAR) device, which can be implanted on the brain surface in rodents for high-resolution neurophysiological recording. We characterize optical transparency of the device at >90% transmission over the ultraviolet to infrared spectrum and demonstrate its utility through optical interface experiments that use this broad spectrum transparency. These include optogenetic activation of focal cortical areas directly beneath electrodes, in vivo imaging of the cortical vasculature via fluorescence microscopy and 3D optical coherence tomography. This study demonstrates an array of interfacing abilities of the CLEAR device and its utility for neural applications.

Technical Approach for Reanimation of the Chronically Denervated Larynx by Means of Functional Electrical Stimulation

1994 ◽  
Vol 103 (9) ◽  
pp. 705-712 ◽  
Author(s):  
David L. Zealear ◽  
Cheryl L. Rainey ◽  
Tetsuya Tanabe ◽  
Matthew L. Jerles ◽  
Garrett D. Herzon
Keyword(s):  
Electrical Stimulation ◽  
Functional Electrical Stimulation ◽  
Vocal Fold ◽  
Hot Spot ◽  
Electrode Array ◽  
Electrode Arrays ◽  
Denervated Muscle ◽  
Alternative Approach ◽  
Bilateral Vocal Fold Paralysis ◽  
Posterior Cricoarytenoid

Functional electrical stimulation (FES) of the posterior cricoarytenoid (PCA) muscle to produce vocal fold abduction offers an alternative approach to current surgical therapies for bilateral vocal fold paralysis. The purpose of this study was to characterize the application of FES to chronically denervated PCA muscles. Specific goals were to develop a stimulus delivery system for the PCA muscle, determine a practical means of implantation, and identify stimulus parameters effective in activating chronically denervated muscle. Seventeen dogs were implanted with planar electrode arrays 3 months after unilateral recurrent laryngeal nerve resection. A nail-bed electrode array allowed discrete activation of the PCA muscle and gave the greatest abductions, with minimal charge dissipation. Muscle mapping revealed hot-spot regions on the PCA muscle surface, in which stimulation produced maximum abduction. A conservative stimulus paradigm effective in activating chronically denervated muscle was a 1-second pulse train of 2-millisecond-duration pulses, delivered at a tetanizing frequency of 30 Hz and an amplitude of 4 to 14 mA.

RF Coupling of Interdigitated Electrode Array on Aerogels for in vivo Nerve Guidance Applications

MRS Advances ◽  
2019 ◽  
Vol 4 (21) ◽  
pp. 1237-1244 ◽  
Author(s):  
Jacob Hadley ◽  
Jack Hirschman ◽  
Bashir I. Morshed ◽  
Firouzeh Sabri
Keyword(s):  
Electrical Stimulation ◽  
Nerve Repair ◽  
Electrode Array ◽  
Silica Aerogels ◽  
Interdigitated Electrode ◽  
In Vivo Models ◽  
Regeneration Rate ◽  
Interdigitated Electrode Array

AbstractAerogels are light-weight porous materials that can tolerate the processing steps required for designing and creating an electric circuit such that the aerogel can be utilized as a substrate for device fabrication. Previous studies have shown the biostability and biocompatibility of polyurea crosslinked silica aerogels both in vivo and in vitro and have demonstrated the potential use of aerogels in biomedical applications. In vitro studies have shown that in the presence of an applied electric field neurites regeneration rate was greater on crosslinked silica aerogels than on tissue culture petridish used as a positive control. Currently, epineural suturing and nerve grafting are the gold standards for surgical reconstruction of injured nerves. However, because they rely on passive mechanisms for reapproximating the distal and proximal terminals they often lead to partial or no recovery leaving room for improvement. The present study investigates the feasibility of a wireless aerogel–based electrically-stimulating implant intended for nerve repair applications. Here the authors report on RF coupling between a secondary coil and a primary coil to wirelessly energize an interdigitated electrode array consisting of eleven interlocking fingers, created on a silica aerogel substrate. The coupling strength was tested both in air and in an animal model, as a function of distance and will be reported. This study focuses on in vivo evaluation and feasibility assessment of a novel active 3-D aerogel-based peripheral nerve repair device. The device utilizes induced EMF to establish a current (hence electrical stimulation) in predetermined pathways where nerve stumps will be confined to. Fundamental differences between in vitro and in vivo models necessitate the in vivo approach. The novel inductively-powered electrical stimulation aerogel-based device utilizes previously established 3-D confinement method for immobilization of nerve stumps, taking advantage of the mesoscopic surface roughness, unique to aerogels. The technique is tested on a mechanically strong, lightweight, porous, and biostable aerogel. Lithographic techniques, gold (Au) thin film metallization, and Faraday induction is used for circuit design, development, and activation.

scholarly journals A Suprachoroidal Electrical Retinal Stimulator Design for Long-Term Animal Experiments and In Vivo Assessment of Its Feasibility and Biocompatibility in Rabbits

2008 ◽  
Vol 2008 ◽  
pp. 1-10 ◽  
Author(s):  
J. A. Zhou ◽  
S. J. Woo ◽  
S. I. Park ◽  
E. T. Kim ◽  
J. M. Seo ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Animal Experiments ◽  
Electrode Array ◽  
Rf Coil ◽  
Stimulation Mode ◽  
Retinal Stimulation ◽  
Implantable Stimulator ◽  
External Component

This article reports on a retinal stimulation system for long-term use in animal electrical stimulation experiments. The presented system consisted of an implantable stimulator which provided continuous electrical stimulation, and an external component which provided preset stimulation patterns and power to the implanted stimulator via a paired radio frequency (RF) coil. A rechargeable internal battery and a parameter memory component were introduced to the implanted retinal stimulator. As a result, the external component was not necessary during the stimulation mode. The inductive coil pair was used to pass the parameter data and to recharge the battery. A switch circuit was used to separate the stimulation mode from the battery recharging mode. The implantable stimulator was implemented with IC chips and the electronics, except for the stimulation electrodes, were hermetically packaged in a biocompatible metal case. A polyimide-based gold electrode array was used. Surgical implantation into rabbits was performed to verify the functionality and safety of this newly designed system. The electrodes were implanted in the suprachoroidal space. Evoked cortical potentials were recorded during electrical stimulation of the retina. Long-term follow-up using OCT showed no chorioretinal abnormality after implantation of the electrodes.

scholarly journals Selective electrical stimulation with currentfield modulation

2021 ◽  
Vol 7 (2) ◽  
pp. 803-806
Author(s):  
Halldór Kárason ◽  
Óskar Pilkington ◽  
Thordur Helgason
Keyword(s):  
Electrical Stimulation ◽  
Electrode Array ◽  
Single Pulse ◽  
Treatment Modalities ◽  
Electrode Arrays ◽  
Current Field ◽  
Temporal Precision ◽  
Specific Stimulation ◽  
Field Modulation ◽  
Electrical Stimulator

Abstract Selective electrical stimulation using a multielectrode array is a promising technique that can potentially bring electrical stimulation treatment modalities a step forward. A microcontroller-controlled electrical stimulator system delivering a single pulse was designed, suitable for current-field modulation. The goal is to make electrical stimulation with surface electrodes more specific. A graphical user interface (GUI) was developed to control stimulation parameters and current-field within a multi-electrode array wirelessly. The stimulator generates arbitrary biphasic waveforms with a 5-bit resolution and high temporal precision (<10 μs) and was demonstrated to stimulate posterior lumbar root fibers in transcutaneous spinal cord stimulation (tSCS) treatment selectively. Current-field modulation throughout a sixteen-electrode array was achieved. The system has the goal to improve control of stimulation conditions in electrophysiological studies and time-dependent and site-specific stimulation patterns for neuromodulation applications. A novel feature is the current-field modulation ability of the stimulator for surface electrode arrays.

scholarly journals Creating Custom Neural Circuits on Multiple Electrode Arrays Utilizing Optical Tweezers for Precise Nerve Cell Placement

2020 ◽  
Vol 3 (2) ◽  
pp. 44
Author(s):  
Frank H. Kung ◽  
Ellen Townes-Anderson
Keyword(s):  
Optical Tweezers ◽  
Neuronal Development ◽  
Neural Circuits ◽  
Electrode Array ◽  
Bipolar Cells ◽  
Electrode Arrays ◽  
Cell Placement ◽  
Multiple Electrode

Precise creation, maintenance, and monitoring of neuronal circuits would facilitate the investigation of subjects such as neuronal development or synaptic plasticity, or assist in the development of neuronal prosthetics. Here we present a method to precisely control the placement of multiple types of neuronal retinal cells onto a commercially available multiple electrode array (MEA), using custom-built optical tweezers. We prepared the MEAs by coating a portion of the MEA with a non-adhesive substrate (Poly (2-hydroxyethyl methacrylate)), and the electrodes with an adhesive cell growth substrate. We then dissociated the retina of adult tiger salamanders, plated them onto prepared MEAs, and utilized the optical tweezers to create retinal circuitry mimicking in vivo connections. In our hands, the optical tweezers moved ~75% of photoreceptors, bipolar cells, and multipolar cells, an average of ~2000 micrometers, at a speed of ~16 micrometers/second. These retinal circuits were maintained in vitro for seven days. We confirmed electrophysiological activity by stimulating the photoreceptors with the MEA and measuring their response with calcium imaging. In conclusion, we have developed a method of utilizing optical tweezers in conjunction with MEAs that allows for the design and maintenance of custom neural circuits for functional analysis.

Tissue reactions to long-term electrical stimulation of the cerebellum in monkeys

1977 ◽  
Vol 47 (3) ◽  
pp. 366-379 ◽  
Author(s):  
W. Jann Brown ◽  
Thomas L. Babb ◽  
Henry V. Soper ◽  
Jeffrey P. Lieb ◽  
Carlos A. Ottino ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Charge Density ◽  
Purkinje Cells ◽  
Molecular Layer ◽  
Electrode Array ◽  
Electrode Arrays ◽  
Human Cerebellum ◽  
A Charge ◽  
Tissue Reactions ◽  
Stimulation Of

✓ Light and electron microscopic analyses were carried out on the stimulated and unstimulated paravermal cortices of six rhesus monkeys that had electrodes implanted on their cerebella for 2 months. The electrodes and the stimulation regime (10 p.p.s.: 8 min on, 8 min off) were similar to those used to stimulate the human cerebellum for treatment of certain neurological disorders. Mere presence of the electrode array in the posterior fossa for 2 months resulted in some meningeal thickening, attenuation of the molecular layer, and loss of Purkinje cells immediately beneath the electrode array. There was no evidence of scarring. After 205 hours of stimulation (7.38 × 106 pulses) over 18 days, a charge of 0.5 µC/ph or estimated charge density of 7.4 µC/sq cm/ph resulted in no damage to the cerebellum attributable to electrical stimulation per se. Such a charge/phase is about five times the threshold for evocation of cerebellar efferent activity, and might be considered “safe” for stimulation of human cerebellum. Charge density/phase and charge/phase were directly related to increased cerebellar injury in the six other cerebellar cortices stimulated. Leptomeningeal thickening increased with increased charge density. Injury included severe molecular layer attenuation, ongoing destruction of Purkinje cells, gliosis, ongoing degeneration of myelinated axons, collagen intrusion, and increased levels of local polysaccharides. In all cases, even with damage that destroyed all conducting elements beneath the electrodes, there was no damage further than 1 to 2 mm from the edges of the electrode arrays.

Automatic control of grasping strength for functional electrical stimulation in forearm movements via electrode arrays

2018 ◽  
Vol 66 (12) ◽  
pp. 1027-1036 ◽  
Author(s):  
Christina Salchow-Hömmen ◽  
Till Thomas ◽  
Markus Valtin ◽  
Thomas Schauer
Keyword(s):  
Electrical Stimulation ◽  
Functional Electrical Stimulation ◽  
Motion Tracking ◽  
Inertial Sensors ◽  
Electrode Array ◽  
Electrode Arrays ◽  
Reach And Grasp ◽  
Automatic Adaptation ◽  
Virtual Electrodes ◽  
Relative Change

Abstract The generation of precise hand movements with functional electrical stimulation (FES) via surface electrodes on the forearm faces several challenges. Besides the biomechanical complexity and the required selectivity, the rotation of the forearm during reach-and-grasp tasks leads to a relative change between the skin and underlying tissue, resulting in a varying FES response. We present a new method for automatic adaptation of virtual electrodes (size, position) and stimulation intensity in an electrode array to guarantee a secure grasp during forearm movements. The method involves motion tracking of arm and hand with inertial sensors. This enables the estimation of grasping strength when using elastic objects. Experiments in healthy volunteers revealed that our method allows generating a strong, stable grasp force regardless of the rotational state of the forearm.

scholarly journals An Open-Source Wireless Electrophysiological Complex for In Vivo Recording Neuronal Activity in the Rodent’s Brain

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7189
Author(s):  
Alexander Erofeev ◽  
Dmitriy Kazakov ◽  
Nikita Makarevich ◽  
Anastasia Bolshakova ◽  
Evgenii Gerasimov ◽  
...  
Keyword(s):  
Open Source ◽  
Neuronal Activity ◽  
Ex Vivo ◽  
Electrode Arrays ◽  
Charging Station ◽  
In Vivo Experiments ◽  
The Brain ◽  
Schematic Diagrams

Multi-electrode arrays (MEAs) are a widely used tool for recording neuronal activity both in vitro/ex vivo and in vivo experiments. In the last decade, researchers have increasingly used MEAs on rodents in vivo. To increase the availability and usability of MEAs, we have created an open-source wireless electrophysiological complex. The complex is scalable, recording the activity of neurons in the brain of rodents during their behavior. Schematic diagrams and a list of necessary components for the fabrication of a wireless electrophysiological complex, consisting of a base charging station and wireless wearable modules, are presented.

Sign in / Sign up

Export Citation Format

Share Document